1. Field of the Invention
The present invention relates to a fixing apparatus used in an electrophotographic image forming apparatus.
2. Description of the Related Art
This type of image forming apparatus is provided as a copy machine, a printer, a facsimile apparatus, or the like. In this apparatus, an electrostatic latent image is formed on a photosensitive body, the electrostatic latent image on the photosensitive body is developed using toner to form a toner image on the photosensitive body, the toner image is transferred from the photosensitive body to recording paper, and heat and pressure are applied to the recording paper to fix the toner image on the recording paper.
Recently, reduction in the size of those various image forming apparatuses has been advancing, reducing excess space inside the apparatus, so that many components are arranged close to each other. Thus, when a jam occurs, in which recording paper in the midst of transport becomes blocked, it is difficult to remove the recording paper. Several opening-closing locations are provided along the transport path so that the transport path is opened by opening these opening-closing locations, but because many components are also disposed around the transport path, even if the transport path is opened, those components may be a hindrance to removing the recording paper. Also, there is a risk that when removing the recording paper, the recording paper will be rubbed against a peripheral component, leading to a reduction in component precision or damaging a component.
In a fixing apparatus, while transporting recording paper sandwiched between a heating roller and a pressure roller, heat and pressure are applied to the recording paper to fix toner on the recording paper by melting the toner with heat, so a jam may occur due to the recording paper rolling around the heating roller or the pressure roller, and thus an opening-closing location is also provided in the vicinity of the fixing apparatus so that it is possible to remove the recording paper.
Also, in the fixing apparatus, a guide member is provided in order to guide the recording paper, but because this guide member hinders the removal of recording paper, a configuration is adopted in which it is possible to move the guide member when removing the recording paper.
For example, in a fixing apparatus according to the related art as shown in FIG. 9, the recording paper is transported sandwiched between a heating roller 101 and a pressure roller 102, the recording paper is guided between a paper separation plate 104 and a guide member 103, and the recording paper is further transported by a transport roller 105. The guide member 103 is rotationally supported axially by a shaft 103a. When a recording paper jam has occurred, the guide member 103 is rotated around the shaft 103a in the direction of arrow C, removing the guide member 103 from the recording paper transport path as indicated by the double-dotted line, and thus the area around the transport path is widely vacated so that the recording paper can easily be removed.
Also, in JP H02-81855A, on the downstream side of the fixing apparatus in the transport direction of the recording paper, a transport mechanism including the transport roller or the like is removed from the fixing apparatus, thus opening the downstream side of the fixing apparatus, so that it is possible to remove recording paper jammed in the fixing apparatus.
However, in order to rotate the guide member 103 around the shaft 103a along the trajectory tr of the double-dotted line as shown in FIG. 9, a large space for evacuating the guide member 103 is necessary, and this space prevents a reduction in the size of the image forming apparatus. Also, the space therefore cannot be made sufficiently large, and even if the guide member 103 is rotated, it is not possible to widely vacate the area around the transport path, and thus the recording paper cannot be easily removed. In addition, when the user makes an excessive attempt to remove the recording paper, there is a risk that the user's hand will touch the heating roller, or that the heating roller 101, the pressure roller 102, the paper separation plate 104, a temperature sensor (not shown), or the like will be damaged.
Also, even in a state with the guide member 103 positioned at a prescribed position when guiding the recording paper, the guide member 103 occupies a large amount of space, and this also prevents a reduction in the size of the image forming apparatus.
Also, as disclosed in JP H02-81855A, in a case in which a transport mechanism including the transport roller or the like is removed from the fixing apparatus, a large space for evacuating the guide member is necessary, thus preventing a reduction in the size of the image forming apparatus.